A lifetime? I like to over use chlorine removers occassionally(twice the normal dose-- just in case-- I'm super cautious). also I'm building a tank 657 gallons or so just for the snapper and maybe a few fish(he/she never takes interest in live food apparently. ._.;Bleach is chlorine, to make chloramine you must combine it with ammonia (5 parts chlorine -1 part ammonia ratio)
You would not need much of the crystal form of chlorine remover (it is either sodium thiosulfate, or calcium thiosulfate). One of those is the active ingredient in all chlorine/chloramine removers. A bucket should last you a lifetime, and the price is a fraction of the cost of the aquarium brands.